Wednesday, March 28, 2012

What is Multimedia Card？

MMC card (Multimedia Card)
is a kind of Flash Memory card standard. It is developed by Simens and SanDisk
in 1997. Based on NAND Flash Memory technology of Toshiba, it is thiner and
smaller than earlier NOR Flash Memory of Intel like CF card. MMC card is as
small as a stamp. That is about 24mm * 32mm * 1.5mm.

IntroductionMMC card is small and light, weighs
only 2g and below. It is strongly resistant to impact, and can repeatedly
read-write and record for 300 thousand times. Driving voltage of MMC card is
2.7-3.6 V. At present the capacity of MMC card is as much as 2 GB. Moreover, it
can be applied to almost every device which uses memory card, such as mobile
phone, digital audio player, digital camera and PDA. Because of the showing up
of Secure Digital, there is no firm which put MMC slot into their devices. Yet a
little bit narrower, Pin to Pin MMC card can be applied to every device supoorts
SD card. However, few firms, best-known Nokia, still supported MMC. At first
MMC card uses serial interfaces, but the newer standard allows concurrently
transmission of 4 bit or 8 bit information. Recent years MMC card technology has
almost replaced by SD card. But as MMC card can be read by device which supports
SD card, it still works.

FeaturesMMC card is released by Simens and SanDisk which
focuse on CF in 1997. January, 1998, 14 companies establish MMC association
(MultiMediaCard Association, MMCA in short.) there are already
84 more members now. The target of MMC development is digital video, music,
cellphone, PDA, e-book, toy, and so on. The size of it is only 32mm * 24mm *
1.4mm, and only weighs 1.5g. MMC also combines storage unit with controller. Smart controller guarantees the
compatibility and flexibility. MMC storage card can be divided into MMC and
SPI two kinds of operating modes. MMC is the normal default mode and has all of
the features of MMC. SPI mode is the second optional mode of MMC storage card.
This mode is a subset of MMC protocol. It is mainly used for system that need
small number of card (usually one), and low data transmission
rate (compared to MMC protocol). This mode can reduce the
design cost to minimum, but the performance is not as good as MMC.

Designed as a low cost data platform and conmmunication medium, the port design
of MMC is very simple: there are only 7 pins. The cost of port is under 0.5
dollar. In the port, power supply used 3 pins and data manipulation uses only 3
pins serial bus (in SPI mode 1 more pin is used for choosing
chip).

The operating voltage of MMC is 2.7-3.6 V. Read-write
current is only 27mA and 23mA. The consumption is very low. The read-write mode
includes stream transmission, multi-piece and single piece. The minimum data
transmission is counted in piece. The default piece is 512 bytes.

RS-MMCThere is small size MMC card. It is half size
of normal size MMC card: 24mm * 18mm * 1.4mm. This optional size MultiMediaCard,
or RS-MMC, is released in 2004. It is only smaller size MMC card. Use a
machinery connection to extend it, any RS-MMC card can be used at MMC
(or SD) card slot. The largest capacity of RS-MMC card can be 1
GB at present.

The only two important hardware licensors of RS-MMC are Simens and Nokia. They
often put RS-MMC card in use of Nokia's 60 series Symbian smart phone, Nokia's
770 Internet tablet PC and Simens' 65 and 75 production. The newer RS-MMC card
applied in Nokia's new phone (like Nokia 6630 and Nokia 6680)
supports low voltage (1.8V, not 3V) mode to reduce power
consumption. These cards are called double voltage RS-MMC
(DV-RS-MMC). If RS-MMC card satisfys the standard of movable
type MMC card, it can be sold as movable type MMC card. These low voltage cards
are backward compatible with old RS-MMC devices. Double voltage card and movable
MMC is part of 4.x standard of MMC.

MMC 4.x and secureMMC

4.x (4.0, 4.1, etc.) standard is released in 2005 (MMCA
system standard 4.1). This new standard brought in MMC4 which is called MMCplus and has more effective
performance (it uses tha same structure and size with MMC but there are
more pins) and RS-MMC4 which is sold as movable MMC. Movable MMC4 is a
reprint of old RS-MMC, because it uses the same way and standard of connection
with RS-MMC. Yet its size is about half of normal MMC card. This standard also
defines secureMMC standard. The encipherment feature is similar to Secure
Digital or MagicGate Memory Sticks.

Different types of MMC/SD cardsSD card is not the only
stsndard of Flash Memory which acquires the admission from Secure Digital Card
Association. Other Secure Digital Card format includes miniSD and microSD
(it is called TransFlash before being admitted by Secure Digital Card
Association).These small size cards can be used in full size
MMC/SD/SDIO slot through a converter (connected to electric circuit and
physical connection). However, the difficult point is t to make
input/output device on SD card size, and it will be more unpractical to make on
smaller size. Because SD slot still supports MMC card, the smaller variant
of MMC which has developed alone also supports SD devices. Different froms
miniSD and microSD (they are totally different from SD. Making machinery
converter is very unpractical), RS-MMC slot keeps being backward
cpmpatible with full size MMC card, because RS-MMC is only shorter than MMC
card. More information about these variant please refer to
MMC.

Other information1. About the brands of MMC:
recently most of users choose PQI. The price of PQI is the lowest, so there are
many fake ones. There are two kinds of PQI. One is the first generation low
speed blue dolphin card. The fake blue cards are at the most. It is suggested
not to buy it. The other one is the second generation orange card. If you want
to buy PQI, it is suggested to buy this kind. Other good brands of MMC:
EagleTec, KingMAX, SanDisk.

2. About the capacity of MMC: generally
speaking, 128M or 256M is enough. From the practical angle of view, MMC is
mainly used for storing application software, ring, and pictures, etc. If there
is no need to watch video on phone regularly, 128 M is enough. Otherwise 256M is
better. A music lover may consider about 256M or bigger one.

3. About
the identification of compatibility of MMC card: when buying a MMC card, it is
strongly suggested to try it to see if it works. And it is not enough if it
"works", it is also important to check the compatibility of the
card. You can set the storage to MMC card, and then take a few minutes video
with sound. If the MMC is not completely compatible, there will be no sound when
playing the video. You can also put a SIS form software into the interal storage
of the phone (smaller than 4M), and then change the file
attribute through SELEQ to "read only". Then when you are
trying the card you can install the software on MMC to see if it works. That is
because changing the file attribute to "read only" avoids the
file disappearing after installation. If there is any need to try other cards,
you can continue installing this file. Pay attention to that when the attribute
is changed to "read only", it no longer can be deleted. So
remember to change it back when you need to delete it.

4. About the
distinguishing of new or used MMC: Check the contact point. Generally there is
no scratch on new card.

5. About the formatting of MMC: Generally MMC
newly bought can be used directly. If there is any need to formatting, just make
sure the battery of phone is full before formatting on the phone. It is very
slow to format the card on the phone. If you use the card reader to format MMC
on computer, you have to change the file layout to FAT (that is
FAT16). Otherwise the FAT32 won't be
identified on the phone.

6. About the basic contents of MMC on 6600:
After formatting on the phone, MMC will automatically form the following 6
contents: images, mp3, sounds, videos, system, and others. ●images - the
direct content is for placing photos and pistures. There is a hidden content
"_paibin" for preview pictures. ●mp3 - for placing mp3
files.●sounds - for placing ring files. There are two folders: digital, for
placing wav files; simple, for placing midi files. ●videos - for placing
video files.●sysetm - for placing system files. It cannot be seen unless
using a FileMan or SeleQ or other software.

Reparation of
MMCThere are usually three kinds of MMC card damage. First,
computer cannot read the card because of having not set password. Second, the
card cannot be formatted because of password. Third one is the I/O mistake.

Computer cannot read the card because of having not set
password.Let's firatly see the problem of not being able to read
the card without setting password. Basically, this problem is caused by the
nonsupport of hot-plug and misoperation of card reader, and that makes logical
error of the card. You can use the Norton disc reparation tool or Hrad Disc
Restoration to repair. No more specific operation process but one point to
mention: if put MMC card into the card reader and the system keeps reading the
card with no response or even apparently dead, and the light of card reader
keeps shining, at this situation, the two afore mentioned tools will not work,
because they can never recognize MMC card. Here is a way I have studied to solve
the problem: find a MMC card with the same capacity and put it into the card
reader. Click the right button "format", and the firmatting
menu will come up, then you unplug the card, the menu will not disappear. At
this time you plug in the problematical card, and then choose
"FAT32" formatting. The process may be very long, or the
Windows cannot finish the formatting. Don't give up, repeat this procedure.
Probably the chance is one-tenth. Once the formatting is finshed, you should
click the right button, choose "attribute", "Error
Check", to repair the bad sector. If there is
any physical damage of MMC card, the process might be very long and slow. After
that, choose "FAT" formatting.

The card
cannot be formatted because of passwordAbout the causes of not
being able to format because of password: the causes may be a great many. Most
of them are the poping up of password after formatting MMC card. Another one is
being locked after reboot because of using SeleQ to set Logo or background with
volume E images or MBM images. There are many other causes, too. The card cannot
be formatted in XP system to solve these problems, because the computer will not
recogniaze the card. I have tried to set password to format but it doesn't work.
The perfect solution at present is to use 9210C or 9300 to format. There is
specific process on the BBS. I have studied two strategies. First, find a KODAK
or CANON camera which support MMC card, and then use the camera to format the
card. Generally it doesn't need password, because compared to the phone, camera
has a simpler setting with no buttons. It is better to choose a lower
configuration as long as it supports MMC. The second way is solve the problem in
the phone which causes the mistake. I have tried this way using QD but it is not
very clear if it works in other phones. The specific process is: install SeleQ
through Bluetooth in the phone storage (If you install it in the card,
"system error" will come up), and then reboot the phone. After that you
will see volum E in the SeleQ. You should delete all of the files of the MMC
card. Then there will be two MMC prefixal files in SYSTEM, volum C. Delete both
of them. The card cannot be read by now, but you can try the first solution now.

I/O mistakeAbout I/O mistake, it's better to send the card
for guarantee repair. It's no use to repair it with disc reparation tool because "I/O
mistake" will directly come up and the computer can never read the
card.

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